[Fenichel]

The Oh-numbers of a gCode program must be unique, and PathPilot will not accept code like

o 100 repeat [5]
    G00 X1
    G00 X2
o 100 endrepeat
o 100 if [#1 GT #2]
    G00 X3
o 100 endif

If the same Oh-number is used in two different filed subroutines, one might expect either that

• their scopes would be construed as limited to their respective files, so the authors of the two subroutines would have no obligation to coordinate their work, or
• PathPilot would complain about the conflict.

In fact, neither of these happens. What seems to happen (I have not done extensive testing to characterize the bug, but I think this is right) is that the second appearance of the Oh-number is ignored, and references to that Oh-number will be taken to refer to its appearance in the subroutine called earlier.

For example, if the calling program is

o <first> call
o <second> call
M30

and the two subroutines are

o <first> sub
    (msg, first)
    M98 P100
o <first> endsub
    o 100  (internal subroutine)
        (msg, first)
        M99 (return to caller)

and

o <second> sub
    (msg, second)
    M98 P100
o <second> endsub
    o 100  (internal subroutine)
        (msg, second)
        M99 (return to caller)

then the output is not first-first-second-second. Instead, it is first-first-second-first.